Kiln for the production of cement



Oct. 13, 1931.

H. ENGEL 1,827,144

KI LN FOR THE PRODUCTION OF CEMENT Filed May 29, 1950 2 Sheets-Sheet l y; .z I

V A V A LWW lnvemor: Hans E096! Q jva Patented a. 13, 1931 UNITED STATES HANS ENGEL, or srn'rrnv, GERMANY KILNTOR THE PRODUCTION OF CEMENT Application filed May 29, 1930, Serial No.

My invention relates to improvements in kilns for the production of cement and like artificial hydraulic mortars in which the raw materialblocks of dried slurryis burnt at a glowing heat and thereby converted into clinker.

The object of the invention is to provide an improved kiln for the purpose set forth in which the advantages olferedby kilns of the old type consisting of a stationary vertical shaft having thick wallsof bricks, and on the other hand by kilns of the revolving type of more recent origin, consisting of a long rotary drum arranged in slightly inclined position, are combined, while-the drawbacks inherent individually to the said known types of kilns are eliminated.

As a matter of fact known to practitioners in this field with stationary kilns of the vertical shaft type there is a tendency of thematerial under treatment to choke the kiln because of being too highly heated in the burning zone and thereby baking and sintering together into large obstructing blocks.

Another drawback consists in the fact that the material under treatment, usuallycon- 'sisting of blocks of different shape and size, is not uniformly distributed within thekiln and will not be-uniformly burnt because the compressed a'irand the gaseous products .of' combustion in passing through the kiln will naturally prefer the passagesof'largercross section and will thus not reach to the same extent other parts of the charge in which the material is more closely assembled and aggregated. 7 On the other hand stationary cement kilns of the vertical shaft type have the advan tage of consuming relativelylittle fuel in as much asthe loss of heat conducted through i and radiating from the thick brick walls of the kiln is obviously much smaller than the loss of heat inherent tokilns of the revolving type consisting of a rotary drum of sheet iron andhaving only a thin lining of refractory material on the inner side of the drum.

Moreover in revolving kilns the drum of which is, in slightly inclined position the material under treatment in passing through the kiln usually covers only a limited section of" 'ney.

457,298, and. in Germany June 25, 1928.

the-inner areausually 'resting on the lower side of the drum and, presenting a rel- I atively small surface to the current of highly heated gaseous products of combustion, will utilize an accordingly small amount of the heat, the larger proportion of which radiates through the walls of therotary drum'or is lost with the gases escaping through the chim- However by reason of the fact that the ma-f terial passingthrough revolving kilnsis constantly stirred up, thus always presenting fresh surfaces to the heating gases the quality of the burnt product is more uniform than in the case of stationary kilns. I

Another advantage consists in the fact that the output of revolving kilns is obviously much larger than of stationary kilns of the same size and that also raw material consisting of relatively small pieces containing fine" lumps "and granules can be satisfactorily treated inrevolving kilns even if charged into the kiln in. somewhat moist condition, without clogging the kiln or impairing the quality of the finished product. i

'As indicated above the invention aims at providing an improved kiln which offers the advantages individually attached to known types of cement kilnsi. e. the stationary and the revolving types which are'briefly" explained above, yet eliminating their drawbacks.

The nature and scope of the invention are briefly outlined in the appended claims and will be more fully understood from the following specification taken together with the accompanying drawings in which Fig. 1 is a vertical cross section through a kiln embodying the features of the invention;

Fig. 2 shows a flattened evolution of a modified form of the bottom of the heating chamber having discharge holes of different size and irregular shape for the purpose explained hereinafter. 1

In contradistinction to thestationarytypes '95 of cement kilns consisting of a vertically arranged heating chamber and to the rotary types of cement kilns in which the heating chamber is arranged at a small angle to the horizontal and in which the material pass-' 1 0 dull canac ing therethrough occupies only a limited section of the whole cross sectional area I propose to arran 'e the rotary heating chamber 10 of the improved kiln at such an angle that the material slowly passing through the chamber will fill up the latter from top to bottom.

I prefer to make the heating chamber 10 in the form of a cylindrical. drum i. e. the cross sectional area of which is subs in tially uniform and to provioc a lid member 11 attached to and closing the upper end of the chamber which has an exhaust hole 12. The latter communicates through fluel3 with the chimney and with a hopper 20 through whichthe inaterialto be treated is is closed by-a bottom member-having a plurality of holes 15, 15" provided therein, throughovhich the burnt cementcclinker is discharged into abin- 3O stationarily fixed underneath the said holes and adapted to close the heating chamber nst the atmosphere. Another stationary member i. e., lid 40. which is preferably structurallyconnccted with the bin 30, serves to close the rest of the discharge holes 15" against the atmosphere.

Any suitable means known per se e. g. rollers 50: '51- and drivinggear 52 may be provided fonrotatahlysup orting the bean ingpchambcr 10 inits specific inclined position an d forslow-ly revolving the latter about its longitudinal axis.-

In the embodiment of my inventionishown inthe drawings bvway sir-temple the heatingchainber i0 is arranged at an angle ity..andconsuming less fuel than ordinary rotarykilns oi l nown typehaving the same outputswould require.

Blowers 60. are provided for supplying compressed air to the h ating char 10, which are connected bypipes 61, 61 with the extreme bottom end of the kilniand witli the bin 30 respectively.

The operation of the kiln if heated by solid fuel is as follows Therawm-r oerial driedi slurry-an d the fuel mireciin appropriate proportions are fed into'the kiln throughtbe hopper F20 until the beating chamber 10 is filled lip-almost to I 'ty.. After the ch are as been set on fire and-wh le the kiln slowly revolves essed a r is blowing iher through the materialunyer' tnient becai at the constant stirring action imparted to it bythe revolving chamber 10 veryeii ecti ely andtunitormlydried.- calcined. burnt into n is d awirto the feet that the material in slowly moving downwardly in a helical path even on becoming rather highly heated so as to sinter and bake will nowhere permanently stick to the walls of the heatchambcr and will not choke the latter because the hottest Zone by reason of the inclined position of the kiln extends at an angle to tl e walls of the heating chamber. Thus the respective sections of the walls will be exposed to the greatest heat only once in each revolution and temporarily while they are allowed to cool during the rest of the revolution by contact with portions Oi the charge which are less hot.

Various changes and modifications may be made in the structural design of rot ry kilns for the production of cement and re artificial hydraulic mortars as described above and in the shape and cooperation of their component parts 'thout substantially r evi. from the spirit and the leading i s oi this invention and sacrificing any 'arta -cs otl ercd by the same. 7

. i grinding and crushing means en asbars or rollers facing the discharge holes 15 may be fired in the bin 30 andare adapted to. cause l'liclar clinkers by coming re peatedly into contact with the said grinding and crushing means to be gradually comminuted. V

Convenient means may be provided at the bottom end of the bin 30'for automatically discharging the clinker at intervals and in l Zmited. quantities.

lu the embodiment of the invention shown in Finn. 1 by way of an example said discharging means comprisea pairot rotary discs 80, arranged in superposed position to and spaced from each other,: said discs having holes provided therein which alternately communicate *ith thedischarge port of the bin.

Fig. 2 represents an evolution of the bottom oia heatingchamber having discharge holes 16 of different size and irregular shape.

My experiments have shown that the provision of holes of irregular shape and size as shown byway of an example tends to facilitate and enhance the discharge of the clinker nroceeding through the grate bars or crushing rollers TO'underneath.

The larger holes in passing over the grate or-rollers 70 will. cause a more rapid clownward movement of the clinker above which contributes to stir up and thus bring forward other portions of the clinker in adjoining sections w ichh eretofore have moved somewhat owl 7d requicd some time to from theheating chamber.

I wish not to be limited to the use of solid fuel such coke in kilns designed according this nvention.

The e may be fired with equal success with tuel suchias combustible gases or liquid fuel.

l lorrrle's 90 may be provided at the circumference of the. heating chamber 10 for introducing combustible gases and (or) compressed air. What I claim is:

V 1. In a rotary kiln for the production of If cement or the like, in combination, aheating chamber of substantially uniform cross:

section having its axis inclined at an angle of substantially 45'.to the horizontal wherec by said chamber is normally substantially 1 filled with material, a lid fixed to the upper end of said chamber and having an exhaust opening therein, means for charging raw 7 material into said chamber, a bottom mem ber secured to the lower end of said chamber and having discharge openings therein, a

hopper mounted below said bottom and adapted to receive material escaping through the openings in the lower part thereof, a plate adjacent said bottom and closing the remain ing openings therein, and means for rotating said chamber and forintroducing air into the lower part thereof. v

2. In a kiln as claimed in claim 1, grinding and crushing means fixed in the upper part of said hopper below said bottom.

3. In a kiln as claimed in claim 1, grinding and crushing means fixed in the upper 7 part of said hopper below said bottom, said last named means comprising a plurality of members spaced apart to form a grate.

4. In a kiln as claimed in claim 1, grinding and crushing means fixed in the upper part of said hopper below said bottom, said last named means comprising a plurality of rollers spaced apart to form a grate.

5. In a kiln as claimed in claim 1, said discharge openings varying in size and shape.

6. In a rotary kiln for the production of cement or the like, in combination, a heating chamber of substantially uniform crosssection having its axis inclined at an angle of substantially to the horizontal whereby said chamber is normally substantially filled with material, a lid fixed to the upper 45 end of said chamber and having an exhaust opening therein, means for charging raw material into said chamber, a conical bottom member secured'to the lower end of said chamber and having discharge openings therein, a hopper mounted below said bottom, the upper edges of said hopper conforming to and abutting a portion of the surface of said conical bottom and to receive material escaping through the openings in the lower part thereof, a plate conforming to the remaining portions of the surface of the conical bottom and closing the remaining openings thereln, and means for rotating said chamber and for introducing air into the lower part thereof. 7

In testimony whereof I have signed my name to this specification;

HANS ENGEL. 

